In the present age known as information-oriented society, various kinds of data are stored, and a variety of databases are constructed. Such databases are meaningless if they are simply stored. The added value and utility value of databases will increase if data groups constituting the stored database can freely be retrieved and subjected to information processing therebetween.
Conventionally, such data have been stored in memory devices of computers, and necessary information has been readout electrically and subjected to arithmetic processing, so as to carry out information processing.